fs.mitm: WIP LayeredFS impl (NOTE: UNUSABLE ATM)

Also greatly refactors libstratosphere, and does a lot of other things.
There is a lot of code in this one.

stratosphere/pm/source/pm_shell.hpp

@@ -30,7 +30,7 @@ enum ShellCmd_5X {
     Shell_Cmd_5X_BoostSystemMemoryResourceLimit = 7
 };
 
-class ShellService final : IServiceObject {
+class ShellService final : public IServiceObject {
     public:
         Result dispatch(IpcParsedCommand &r, IpcCommand &out_c, u64 cmd_id, u8 *pointer_buffer, size_t pointer_buffer_size) override;
         Result handle_deferred() override;